Field of the Invention
The present invention relates to a cover for chip suction (which will be hereinafter referred to as a “chip suction cover”) and a machine tool.
Description of the Background Art
As to conventional chip suction covers, for example, Japanese Patent Laying-Open No. 2003-94216 discloses a workpiece holding apparatus aiming to suck chips so as to be reliably removed while ensuring a sufficient amount of air inflow required for sucking the chips without impairing the function of preventing displacement and lift of a workpiece.
The workpiece holding apparatus disclosed in Japanese Patent Laying-Open No. 2003-94216 includes a bushing body through which a drill attached to a spindle is inserted. The bushing body has an inner circumferential surface provided with four ribs that come into contact with the workpiece. These four ribs are arranged so as to protrude inward in the radial direction. The four ribs are arranged such that their tip end portions are spaced apart from each other at a distance through which the drill can pass. The busing body has a lower end having a circumferential edge provided with an intake groove that is opened outward. The intake groove is provided so as to communicate with a groove-shaped space between the ribs adjacent to each other.